大体积混凝土裂缝成因分析及温控措施

Analysis on Crack Cause of Massive Concrete and Measures of Temperature Control

天津子牙河拱桥主墩位于软土地基上,采用了大型承台和重力式桥墩,均属于典型的大体积混凝土块体,且墩柱混凝土全断面一次性浇注完成。该文采用大型有限元软件Ansys分析了温度应力分布,揭示了大体积混凝土结构在温度和收缩作用下裂缝产生的机理。文章介绍,在施工过程中通过减小混凝土内外温差、降低外界条件对混凝土变形约束、提高混凝土自身抗裂能力等措施,有效控制和减小了大型承台和重力式矩形墩柱裂缝的产生。

The main pier of Tianjin Ziya River Arch Bridge is located on soft soil subgrade. The used largesized abutment and the gravity pier and abutment are the typical massive concrete blocks and the full section of the pier stud concrete is poured completely once. The article uses the largescale finite element software Analys to analyze the distribution of temperature stress and reveal the mechanism causing the cracks of massive concrete structure under temperature and shrinkage effect. The article introduces the measures of decreasing the temperature difference between inside and outside the concrete, reducing the deformation constraints of concrete by the external conditions and improving its own anticracking capacity of concrete in the course of construction so as to efficiently control and decrease the cracks of the large base slab and gravity rectangular pier stud.